I use dermmatch first. I've evolved my routine a lot.
I apply it dry around hairline and where I have some coverage. This method makes my hairline look very real and no worries of wind giving away the illusion by showing a painted scalp.
I apply it wet near crown. I also style my hair to help conceal my bad spots.
I use caboki fibers and only put a bit near crown and a little bit near mid section. A bottle lasts me a few months, 4 to 6 typically. The dermmatch does the heavy lifting.
I have been at a concert where it downpoured for 2 straight hours... no problems. Looks very natural when wet, but then it dries kinda off... so need to either redo it or add fibers to remove shine.
Once it is locked in it doesn't come off on hands or from sweat with my method.
Fibers alone will look like sh*t in rain.
If I go on rollercoasters or know I'll be in high winds I use some hairspray. Before this covid sh*t I was going to universal studios in Florida every weekend... I ride everything and never once had an issue. I'm paranoid about it sometimes if I get hit with the wind hard from certain angles, and have my fiancee check, but there has never once been an issue.
I redo it every 2 to 3 days.